The preparation of high quality heterostructure photonic crystals by using pulse anodization and their enhanced photocatalytic property

The TiO2 nanotube heterostructure photonic crystals (HPCs) with high quality photonic band gap (PBG) and more photonic band edges have been prepared by using the pulse anodization with compensation voltage. It is found that when the hetero-structure is introduced on the top of the whole HPC, its structure becomes more uniform and more band edges with high quality PBG appear in the whole visible range, which greatly enhance the light absorption of PC photocatalyst due to the higher photonic state density, and further improve its photocatalytic performance. Furthermore, the matching of PBG red and blue edges with the RhB absorption peak also has effect on the photocatalytic performance. And the HPC has two closely adjoining PBGs and their band edges are simultaneously matched with the RhB absorption peak, which make the HPC have the strongest photocatalytic enhancement.